Cancer appears in more than 100 different forms that affect nearly every part of the body. Throughout life, healthy cells in the body divide, grow, and replace themselves in a controlled fashion. Cancer results when the genes dictating this cellular division malfunction and cells begin to multiply and grow out of control. A mass or clump of these abnormal cells is called a tumor. Not all tumors are cancerous. Benign tumors, such as moles, stop growing and do not spread to other parts of the body. Cancerous or malignant tumors, however, continue to grow and smother healthy cells, interfere with body functions, and draw nutrients away from body tissues. Malignant tumors can spread to other parts of the body through a process called metastasis. Cells from the “mother tumor” detach, migrate via the blood or lymphatic vessels or within the chest, abdomen or pelvis, depending on the tumor, and they eventually form new tumors elsewhere in the body.
Cancer in the kidney constitutes about 3% of all solid tumors. About 85% of renal tumors are classified as renal cell carcinoma (RCC) Approximately 80% of diagnosed RCC originate from the epithelial cells lining the proximal parts of the kidneys' urine-forming ducts, the tubuli. Due to its appearance under the microscope, this cancer type is known as either renal clear cell carcinoma (RCCC, 65%) or renal papillary cell carcinoma (RPCC, 15%). While RCCC and RPCC constitute 80% of diagnosed RCC, they are responsible for closer to 100% of the deaths from renal cell carcinoma.
The most important factor in predicting prognosis is the stage. The stage describes the cancer's size and how deeply it has spread beyond the kidney. The Staging System of the American Joint Committee on Cancer (AJCC) is known as the TNM system. The letter T followed by a number from 1 to 3 describes the tumor's size and spread to nearby tissues. Higher T numbers indicate a larger tumor and/or more extensive spread to tissues near the kidney. The letter N followed by a number from 0 to 2 indicates whether the cancer has spread to lymph nodes near the kidney and, if so, how many are affected. The letter M followed by a 0 or 1 indicates whether or not the cancer has spread to distant organs.
Stage I: The tumor is 7 cm (about 2¾ inches) or smaller, and limited to the kidney. There is no spread to lymph nodes or distant organs.
Stage II: The tumor is larger than 7.0 cm but still limited to the kidney. There is no spread to lymph nodes or distant organs.
Stage III: Includes tumors of any size, with or without spread to fatty tissue around the kidney, with or without spread into the large veins leading from the kidney to the heart, with spread to one nearby lymph node, but without spread to distant lymph nodes or other organs. Stage III also includes tumors with spread to fatty tissue around the kidney and/or spread into the large veins leading from the kidney to the heart, that have not spread to any lymph nodes or other organs.
Stage IV: This stage includes any cancers that have spread directly through the fatty tissue and the fascia ligament-like tissue that surrounds the kidney. Stage IV also includes any cancer that has spread to more than one lymph node near the kidney, to any lymph node not near the kidney, or to any other organs such as the lungs, bone, or brain.
Detailed definitions of renal cell cancer, T, N, M categories, and stage groupings:
Primary Tumor (T):
TX: Primary tumor cannot be assessed
T0: No evidence of primary tumor
T1: Tumor 7 cm or less, limited to kidney
T2: Tumor greater than 7 cm, limited to kidney
T3: Tumor extends into major veins/adrenal/perinephric tissue; not beyond Gerota's fascia
T3a: Tumor invades adrenal/perinephric fat
T3b: Tumor extends into renal vein(s) or vena cava below diaphragm
T3c: Tumor extends into vena cava above diaphragm
T4: Tumor invades beyond Gerota's fascia
N—Regional Lymph Nodes
NX: Regional nodes cannot be assessed
N0: No regional lymph node metastasis
N1: Metastasis in a single regional lymph node
N2: Metastasis in more than one regional lymph node
M—Distant Metastasis
MX: Distant metastasis cannot be assessed
M0: No distant metastasis
M1: Distant metastasis
As a rule of thumb, cancer in stage I or II is treated by surgical removal of the afflicted kidney and the prognosis for recovery is good. In contrast, renal cancers of stage III or IV are associated with very low survival rates, and the National Cancer Institute states on its website that “Virtually no patients with renal cell cancer in stage 1V can be cured.”
The National Cancer Institute estimates 49,096 new cases of renal cancer to be diagnosed in the U.S. in 2009 (16/105 citizens) with 11,033 ensuing deaths (3,6/105 citizens). the corresponding numbers for the European Union (2006) are 65,051 diagnoses (7,8/105 citizens) and 27,326 deaths (3,3/105 citizens) (European Cancer Observatory: http://eu-cancer.iarc.fr/cancer-19-kidney.html,en). Worldwide estimates (2006) are 209,000 diagnosed cases (3,2/105 citizens) and 102,000 deaths (1,6/105 citizens) (Gupta et al. Cancer Treat. Rev. 34, 193-205; 2008). The seemingly higher incidence in the U.S. is due to the fact that the NCI co-reports cancer of the renal pelvis (which is relatively easy to treat) with renal cell carcinomas. The lower global incidence and death rates are likely due, at least in part, to under diagnosis in large areas of the Third World.
The main problem with conventional art is that, as mentioned above, the outcome for any one patient diagnosed with renal cancer is dictated largely by the timing of the diagnosis. If the disease is diagnosed before the tumor has spread outside the kidney the chance for survival is good, otherwise most patients die from the disease. The main reason for this is that renal cell carcinoma is refractory to all conventional therapy with cytostatic and/or cytotoxic drugs, such as cisplatin, carboplatin, docetaxel, paclitaxel, fluorouracil, capecitabine, gemcitabine, irinotecan, topotecan, etoposide, mitomycin, gefitinib, vincristine, vinblastine, doxorubicin, cyclophosphamide, celecoxib, rofecoxib, and/or valdecoxib.
Various solutions are described in the prior art. Conventional chemotherapy against renal cell carcinoma is generally contraindicated due to poor effectiveness and extensive side effects. Alternative treatment modalities have thus been sought, and they can be divided into several categories:
1) Antiangiogenesis. In this strategy the tumor is denied nutrients and oxygen through inhibition of formation of the blood vessels necessary for supplying the tumor tissue. This can be achieved in several ways: 1a) inhibition of circulating growth factors, such as VEGF, PDGF, and PlGF, by treatment with antibodies directed against these growth factors; 1b) blocking of receptors for vascular growth factors on target cells with antibodies directed against the receptors; and 1c) treatment with smaller molecules that interfere with receptor function in such a way that binding of a vascular growth factor to its receptor fails to elicit the physiological angiogenetic effect.
2) Immunomodulatory treatment. This strategy attempts to stimulate the endogenous immune system to recognize the tumor cells as alien and start fighting them. Immune stimulation as treatment against renal cancer takes two main routes: 2a) treatment with interleukin 2 (IL-2); and 2b) interferon alpha (IFNα) therapy.
All of the alternative treatment strategies mentioned above significantly improve the life span of some patients with renal cancer in an advanced stage. However, the effect is in the order of only a few months, and the treatment is associated with numerous serious side-effects. Very often the tumor adapts to the treatment which then has to be discontinued. This is followed by an accelerated rate of tumor growth. Recent strategies for the treatment of renal cancer have been reviewed by Garcia et al. (“Recent progress in the management of advanced renal cell carcinoma.” CA Cancer. J. Clin. 57(2): 112-25 (2007)) and by Atkins et al. (“Innovations and challenges in renal cell carcinoma: summary statement from the Second Cambridge Conference.” Clin. Cancer. Res. 13(2 Pt 2): 667s-670s (2007)).
A review of the literature indicated that many of the therapeutic approaches originate from the identification of more or less specific cancer markers and the use of these markers to elicit a host immune response directed against the invading tumor tissue. Thus, US2006134708 discloses several molecular markers of kidney and urothelial cancer, namely IGFBP-3 (insulin-like growth factor-binding protein 3), ANGPTL4 (angiopoietin-like 4) and ceruloplasmin, as well as monoclonal antibodies directed against said markers, for diagnostic purposes. The use on the peptide and nucleic acid level of antisense compounds directed against the disclosed markers is described. Also, the use of monoclonal antibodies against the markers, the antibodies being conjugated to cytotoxic agents, is contemplated as a therapeutic embodiment associated with less severe side-effects of the cytotoxic agents due to the targeting afforded by the antibody (aka the “magic bullet” concept). A similar strategy, based on different tumor-associated antigens, is adopted in CN1359941.
U.S. Pat. No. 6,403,373 discloses nucleic acid molecules associated with colon, renal and stomach cancer, the peptide products of which gives rise to antibody production in a host. Use of the peptides in a vaccine approach is contemplated. EP0160250 discloses monoclonal antibodies for the diagnosis of renal carcinoma, and mentions the possibility of conjugating these to various cytotoxic agents.
WO2007059082 discloses the occurrence of the antigen TIM-1 (T cell, immunoglobulin or mucin domain 1), which is associated with cellular proliferation, in ovarian and renal cancer. The use of antibodies raised against TIM-1 for the treatment of ovarian and renal cancer is taught, as is the conjugation of therapeutic agents (toxins, radioisotopes or chemotherapeutic agents) to said antibodies as a means of targeted killing of tumor cells.
U.S. Pat. No. 6,440,663 discloses a number of genes expressed by renal cancer cells, the products of which lead to antibody production in the host. Various approaches to eliciting or augmenting an immune response in the host towards the tissue expressing the disclosed genes are described, including the raising of cytotoxic T-cells and transfection of host cells with the disclosed genes or fragments thereof, followed by reintroduction of said cells into the host.
US 2005261178 discloses the co-administration of a monoclonal antibody (G250), directed against an antigen (carbonic anhydrase IX) expressed on the majority of renal cancers, and the cytokines Interleukin-2 or Interferon-α. The cytokines were administered in lower doses than those used when treating with cytokines only. Stabilization of the disease for 22 weeks or longer, or an “objective response”, was achieved in about 30% of the patients in a group suffering from advanced renal cancer.
Other approaches are based on the use of known therapeutic substances in new treatment regimes. For example, WO2007044015 discloses the use of previously known dimethane sulfonate compounds, in particular NSC-281612, according to a new administration protocol in order to treat renal cancer. When tested on xenografts in nude mice, administration of NSC-281612 led, in some cases, to apparently complete eradication of the tumor mass.
JP2001288110 discloses the conjugation of interferon-α to polyethylene glycol (PEG) in an attempt to increase circulating half-life and decrease the smallest therapeutically effective dose.
RU2188026 discloses a polychemotherapy regimen with vincristine, adriamycin and depo-provera. This is claimed to increase the relapse-free period and diminish metastasis formation.
Finally, in a few instances, suggested therapy is founded on new original substances. Thus, WO2004075887 discloses the use of 1-(2-chloroethyl)-1-nitroso-3-(2-hydroxyethyl)urea (HECNU) for the treatment of many cancer types, including renal cancer. The main feature of HECNU is an improved water solubility compared to the previously known corresponding compound, Bis-(2-chlorethyl)-1-nitroso-urea (BCNU).
EP1712234 discloses the use of 4-pyridylmethyl-phthalazine derivatives as VEGF receptor inhibitors in the treatment of renal cancer, especially for the inhibition of metastatic growth. It was found that co-administration of the 4-pyridylmethyl-phthalazine derivatives with either of a plurality of conventional chemotherapeutic agents had a synergistic effect, even though the tumor cells are refractory to the chemotherapy alone. Further, combination therapy was associated with noticeably smaller side-effects.
Suthpin et al. (“Targeting the Loss of the von Hippel-Lindau Tumor Suppressor Gene in Renal Carcinoma Cells”, Cancer. Res. 67(12), 5896-5905 (2007)) studied the selective effect of Chromomycin A3 on renal cancers not expressing the VHL gene (this tumor-suppressing gene is absent in about 70% of all renal clear cell cancers). Chromomycin A3 significantly retarded tumor growth in xenografted nude mice without affecting normal renal tissue, expressing the VHL gene.
The invention herein utilizes Orellanine (Formula I), which is a selective renal toxin occurring in relatively large amounts in several fungal species of the Cortinarius family. Intoxication with orellanine after confusion of Cortinarius fungi with edible mushrooms occurs regularly throughout Europe, Russia and North America. After ingestion of orellanine-containing fungi, there is a period of a few days up to 3 weeks with no symptoms or only mild, influenza-like symptoms. The next phase, when medical help is generally sought, is characterized by uremia due to acute renal failure. Despite many descriptions of orellanine poisoning in the scientific literature, no other effects of orellanine have been reported apart from the renal toxicity just mentioned (Danel V C, Saviuc P F, Garon D: Main features of Cortinarius spp. poisoning: a literature review. Toxicon 39, 1053-1060 (2001).). This selectivity most likely resides with the fact that orellanine is taken up specifically by one cell type, i.e., the tubular epithelial cells, particularly the proximal tubular epithelial cells (Prast H, Pfaller W: Toxic properties of the mushroom Cortinarius orellanus (Fries) II. Impairment of renal function in rats. Arch Toxicol 62, 89-96 (1988).). The toxin mechanism of Orellanine has not been elucidated, and no treatment is available except maintenance dialysis while waiting to see whether the kidneys will recover or not. The final outcome is critically dependent on the amount of toxin ingested, and, as a rule of thumb, ingestion of one fungus gives temporary problems, two fungi leads to permanent loss of part of the renal function whereas three or more fungi results in total loss of renal function and lifelong need for dialysis or renal replacement therapy.
The applicants have recently published a first study of the mode of action of Orellanine in healthy rats (Nilsson U A et al. The fungal nephrotoxin orellanine simultaneously increases oxidative stress and down-regulates cellular defenses. Free Rad. Biol. Med. 44:1562-9 (2008).). This study shows increased oxidative stress in cortical renal tissue along with dramatically decreased expression of several key antioxidant genes. During this work it was realized that the seemingly absolute specificity of Orellanine for renal tubular epithelial cells could theoretically be extended to encompass these cells also after their transformation into cancer cells. If proven true, such a hypothesis would mean that Orellanine is a powerful weapon against renal cancer of epithelial origin, with curative potential even in advanced stages and with metastases in other tissues.
Pursuing this hypothesis, it was surprisingly discovered that Orellanine was indeed taken up also in human renal cancer cells, and killed them with great efficiency whether they were derived from a primary tumor or from metastatic tumor tissue. The cell death progressed for many days after transient exposure to Orellanine, indicating that the toxin was actively taken up and retained by the cells.